Brake



Nov. 2s, 1933;.` H, E PARKER 1,936,878

BRAKE Filed May 17, 195o IN V EN TOR.

HUMPHREY E PARKER A TTORNEY Patented Nov. 28, 1933 PATENT olv-FICE BRAKE Humphrey F. Parker, South Bend, Ind., assignor to Bendix Brake Company, South Bend, Ind., a corporation of Illinois Application May 17, 1930. seria1No.453,387

1 Claim.

This invention relates to brakes and more particularly to internal expanding brakes.

An object of the invention is to increase the braking effect.

Another object of the invention is to provide an eiiicient operating means for the friction element.

A further object of the invention is to provide an operating means for the friction elements adapted to actuate one of the friction elements for engagement slightly in advance of the other.

An important feature of the invention is a rock lever having thrust rollers on its respective ends engaging the rims of the friction elements.

Another important feature of the invention is a rock lever having one arm longer than the other and means for actuating the rocking lever, including an eccentric, to move the primary shoe against the drum slightly in advance of the engagement of the secondary shoe with the drum. Yet another feature of the invention is an expansible device for adjusting the relative position of the friction elements.

Other objects and features of the invention will more fully appear from the following description, vtaken in connection with the drawing, and in which:

Figure 1 is a side elevation of a brake mechanism embodying the invention;

Figure 2 is a section substantially on, line 2 2, Figure l; and

Fig-ure 3 is a section substantially on line 3-3, Figure 1.

Referring now to the drawing in detail and in which like reference numerals designate similar parts throughout the several views, l0 indicates a fixed support such as a backing plate which may be secured to an axle or to a spindle, not shown, and associated with the backing plate is a rotatable drun 11 adapted to be secured to a wheel.

Positioned on the backing plate are anchors 12 and 13 and steady rests 14 and 15. These anchors and steady rests support the friction elements. AS shown, the anchor 12 and steady rest 14 support a primary shoe 16, and positioned on the anchor 13 and steady rest 15 is a secondary shoe 17. These shoes are of the conventional type, each comprising a rim 18 and a web 19, the rim having secured thereto, a suitable lining 20, adaptable for engagement with the radius of the drum. The articulating ends of the shoes 16 and 17 are connected by an adjustable member included generally at 21 to be hereinafter described.

(Cl. 18S-78) diate the separable ends of the shoes 16 and 17, is a sleeve 22, and positioned for rotation inthe sleeve is an operating shaft 23 having formed thereupon a pin 24 positioned eccentric to the axis of the shaft. Positioned for oscillation onA the pin 24 is a rock lever 25, suitably secured on the pin as by a washer 26 and a cotter pin 27. The free ends of the rock lever 25 have suitably mounted thereon, thrust rollers 28 and 29, engaging the rims of the respective primary and secondary shoes 16 and r17.

It is to be observed that the rocker arm 25 has one arm longer than the other and that the shorter arm carries the thrust roller 28 engaging the rim of the primary shoe. This is an important factor in that it provides a structure whereby the primary shoe is moved to engage the radius of the drum slightly in advance of the engagement of the secondary shoe with the drum.

. As shown, the primary and secondary shoes 'are connected by a coil spring 30 and the articulated end of the primary shoe is connected by a coil spring 3l to a fixed support 32. These springs function to return the shoes to the off position and to retain them in engagement with an adjustable stop 33 positioned on the backing plate where 'they are held with their rims in proper spaced relation to the radius of the drum.

The articulating ends of the shoes are apertured to receive studs or bolts 34 and 35 upon which are pivoted plates 36 and 37. These plates are arranged in overlapping position and are provided with registering slots 38 and 39, having bevelled portions 40 and 41. As shown, the bevels are in opposite directions and the slots extend one past the other. The plates are secured together by means of a clip 42 having a rectangular flange 43 apertured as indicated at 44. This aperture registers with the registering slots 38 and 39 in plates 36 and 37.

A wedged shaped member 45 is positioned in the registering slots in the plates. This member is centrally tapped to receivev a` screw 46 having a head 47. The screw 46 extends through the aperture 44 in the fiange 43 and is provided with a washer 48 having a bearing on the flange 43 on the opposite side of the flange from the member 45. The screw is positioned immediately opposite an opening in the backing plate so that adjustment of the member 45 may be readily made from the outside of the brake.,

In operation the screw 46 is turned by its head 47 to cause the member 45 to travel forward or backward on the screw and by reason of this movement the relative position of the plates 36 and 37 may be adjusted to contract or expand the articulated ends of the shoes.

1,936,878 I A brake comprising a support, a rotatable drum associated therewith, primary and secondary friction elements positioned on the support and -selectively -anchored at their separable ends. an

adjustable member connecting the articulating ends of the friction elements, means for engaging the primary and secondary friction elements with the drum comprising a rock arm having one arm longer than the other, means for operating y the rock arm to actuate the primary friction elements slightly in advance of the secondary shoe, and a pair of anchors for said separable ends arranged on opposite sides of said rock arm.

` HUMPHREY F. PARKER. 

